Intake manifold construction



Sept. 25, 1956 D. D. STONE INTAKE MANIFOLD CONSTRUCTION Filed Feb. 26, 1954 2 Sheets-Sheet l 46 -46 r44 42 3G Era! 34' /4 16 m 50 1 8 J L. J' LN--- 30 18 INVENTOR. 90 DONALD D. STONE [/0 BY I m- 5, 1956 D. D. STONE INTAKE MANIFOLD CONSTRUCTION Filed Feb. 26, 1954 2 Sheets-Sheet 2 United States Patent INTAKE MANIFOLD CONSTRUCTION Donald D. Stone, Flint, Micl1., assignor, by mesne assignments, to Bank of America National Trust and Savings Association, San Francisco, Calif.

Application February 26, 1954, Serial No. 412,814

4 Claims. (Cl. 123-52) This invention relates to manifold construction for conveying a fuel-and-air mixture into the cylinders of a multicylinder, internal-combustion engine and, more es pecially, to an intake manifold having sections or chambers individually connected with charge-forming devices for conveying fuel-and-air mixture to groups of cylinders.

In multicylinder engine constructions for vehicles, more especially in engines having 4, 6 or 8 cylinders, it heretofore has been customary to utilize a single chargeforming device or'carburetor for supplying fuel mixture through a single manifold chamber or passage to all the cylinders. In such cylinder arrangements, adjacent cylinders are not fired successively; hence, during engine operation, the How of fuel-and-air mixture in the intake manifold or mixture-distributing device is subjected to continuous changes in direction. Furthermore, the use of a single charge-forming device or carburetor for a multicylinder engine requires the fuel-and-air mixture to move through widely varying distances from the chargeforming device to the several cylinders. This condition tends to result in an over-rich mixture being supplied to the cylinders positioned near the charge-forming device and a lean mixture being delivered to the cylinders positioned a greater distance from the charge-forming device. An arrangement of this character does not provide an etficient distribution of fuel and air to the engine cylinders, resulting in a substantial loss of power and fuel efficiency.

Endeavors have been made to utilize more than one charge-forming device or carburetor through the employment of an independent mixture-intake manifold for each group of engine cylinders. However, such arrangements have not been entirely satisfactory as the pressures in one manifold may vary considerably from the pressures in an adjacent manifold, resulting in uneven explosion pressures and impairing smooth operation of the engine.

Where two carburetors are used, it is advantageous to mount the same in a manner so that one carburetor is adapted to supply fuel mixture to one manifold chamber arranged adjacent one group of consecutively arranged cylinders, the other carburetor being disposed to convey a mixture through a second manifold chamber to another group of consecutively arranged cylinders in the engine construction. For example, in a 6-cylinder engine, the group of three cylinders in the front portion of the block would be associated with one manifold section and the remaining three cylinders would be associated with a second manifold chamber, each of the chambers being provided with a separate charge-forming device or carburetor.

A usual or conventional firing order of cylinders in a 6-cylinder engine is 1-5-3-62-4. Thus, when the mixture is ignited in #1 cylinder, the cylinder is being supplied with mixture from the carburetor adapted to feed mixture to the second group of cylinders. While the mixture in #5 cylinder is being ignited, as its firing succeeds that of #1 cylinder, the carburetorrassociated with the second group of cylinders is idle while the mixture is being supplied to #3 cylinder from the carburetor adapted to supply mixture to the first group of cylinders. Hence, the carburetors are brought into operation alternately and, therefore, have alternate periods of idleness in which they are not supplying mixture to any cylinder. After an idle cycle or period, the carburetor is subjected to suetion or reduced pressure on the fuel mixture inlet cycle of a cylinder, an air stream must be set in motion through the carburetor, and fuel must likewise be moved through the carburetor through the main jet thereof into the air stream to deliver mixture to the cylinder requiring same. After the mixture feed cycle of the said cylinder is completed, the suction or reduced pressure effective on the carburetor ceases, and no fuel or air is discharged from the carburetor. This condition obtains until the cylinder in the opposite group which is next in firing order is supplied with mixture from the other carburetor. Such alternate periods of operation and idleness of each carburetor continue as long as the engine is operating. This arrangement does not provide a smoothly operating engine, nor does it supply uniform mixtures or charges of fuel and air to the several cylinders.

The present invention relates to a manifold construction for use with a plurality of charge-forming devices or carburetors wherein individual chambers or sections of the manifold are interconnected so as to provide for the equalization or balancing of pressures in the manifold chambers.

An object of the invention resides in the provision of a manifold construction for a multicylinder, internalcombustion engine wherein groups of cylinders are supplied with fuel mixture through substantially independent manifold chambers arranged in a manner in which each chamber is supplied with fuel mixture from an independent charge-forming device, the chambers of the manifold arrangement being in communication with each other by means of a restricted passage, whereby a degree of suction or reduced pressure is effective at all times on the charge-forming devices or carburetors during engine operation.

Another object of the invention resides: in a dual-cam buretor arrangement and manifold construction for a multicylinder, internal-combustion engine wherein spaced, mixture-conveying chambers in the manifold construction are connected by means facilitating restricted flow of fuel mixture from one chamber to the other so that both carburetors are functioning at all times during engine operation whereby a more uniform fuel-and-air mixture is supplied to the several cylinders of the engine.

Another object of the invention is the provision of a multichambered, intake manifold arrangement for use with an internal-combustion engine wherein each manifold chamber receives the major portion of fuel-and-air mixture for a group of cylinders from one carburetor and concomitantly receives a minor portion of the fuel-andair mixture required for another group of cylinders from another carburetor whereby both carburetors operate at all times to feed major and minor portions of fuel-mixture charges to the cylinders of the engine.

, Another object of the invention is the provision of an engine manifold construction of an integral character formed or shaped with a plurality of mixture-receiving chambers arranged in spaced relation with a restricted passage formed within the manifold, establishing restricted communication between adjacent chambers.

Another object of the invention is the provision of a manifold construction fabricated as a single unit, embodying a plurality of spaced, mixture-receiving chambers and including a removable tube disposed adjacent the chambersformetering the flow of fuel mixture from one chamber into an adjacent chamber and which may be replaced by one having a passage of different size.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and, function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which: I

Figure l is a side elevational view of an internalcom'bustion engine embodying a form of the invention;

FigureZ is a vertical sectional view through the upper portion of the engine construction shown in Figure 1;

Figure 3 is a horizontal sectional view taken through the cylinder head and manifold construction of the en-' gine shown in'Figure lfand Figure 4 is a fragmentary, horizontal, sectional view showing a modified form of'the invention.

While the arrangement of the invention is illustrated embodied in an internal-combustion engine having six cylinders arranged in line in which two manifold chambers respectively convey mixture to two groups of three cylinders eachfit is to be understood that the invention is applicable to engines having a different number of cylinders in which groups of cylinders'are supplied with fuel mixture ffrom a plurality of manifold chambers.

Referring to the 'dravvingsin detail and initially to Figure 1, the illustrated internal-combustion engine is of thee-cylinder type and includes a cylinder block 19 in which cylinders 11, one of which is shown in Figure 2, are formed. Disposed beneath the engine block ill is an oil pan12. The engine is adapted to be cooled by circulation of water from a cooling radiator (not shown) entering the lower part of 'the block through a tube (not shown). A water-return tube 14 is connected with the cooling radiator to return heated water from the engine to the radiator. Disposed forwardly of the engine is a fan 16 riven by means' of a flexible belt 18 which overtakes a pulley 2%) connected at the extremity of camshaft 22 whereby the fanis rotated to set up air flow through the radiator by operation of the engine. A generator 24, mounted at the side of the engine, has a shaft equipped with a pulley 26 engaged by the belt 1% for driving the generator.

Disposed upon and supported by the engine block is a cylinder head 30 having a manifold construction 32, preferably integrally cast with'the cylinder head 30, ar-

ranged to conveyfuel-and-air mixture into the engine cylinders in the manner hereina-fter described The cylinder head is secured to the block 10 by means of rods 31, shown in Figure 3, adapted to receive securing nuts (not shown). Mounted upon the cylinder head 30 is a sheet metal closure or cover 34 enclosing the valve-operating mechanism, which is secured in'po-sition by means (not shown), for the mixture-inlet valves of the engine. The closure 34 is provided with an oil filler opening normally closed by a cap' 36.

In the illustrated form of the invention, the intake manifold construction includes spacedfelo-ngated chambers or sections 38 and 40, particularly shown in Figure 3.

The chamber 38 is supplied with fuel-and-air mixture by a charge-forming device or carburetor 42, and the chamber 40 is supplied with fuel and-air mixture by a separate charge-forming device or carburetor 44. The carburetors are mounted on the manifold construction 32 in the manner illustrated in Figures 1 and 2. The carburetors bustion chambers and cylinders of the engine.

gine cylinders.

controlling the throttle valves of the carburetors. The arms 50 are connected by suitable means (not shown) and to the accelerator pedal of the vehicle in which the engine is installed, whereby the throttle valves of the carburetors are actuated simultaneously to control the engine speed through control of the fuel-and-air mixtures supplied from each carburetor to the cylinders of the engine. Liquid fuel, such as gasoline, is supplied to the carburetors through suitable feed tubes, one of which is shown -at54 in Figure 2.

With particular reference to Figure 2, each of the cylinders 11 is equipped with a piston 56 which is con nected by means of a Wrist pin 57 with a connecting rod 58, the lower ends of the rods being connected with the crankpins of a crankshaft (not shown) journaled in the lower portion of the engine block it The pistons 56 are arranged for reciprocation in the cylinders 11 in the conventional manner.

The cylinder head 30 is formed adjacent each cylinder with a mixture inlet port 60, a valve 62 being arranged to open and close the port 60. An inlet valve s2 is pro vided for each of thecylinders in the manner shown in Figures 2 and 3. Each valve 62 is formed with a stem 64 slidably mounted in a guide sleeve or bushing 65, the upper end of the valve stem being equipped with an abutment or Washer'67. Disposed between the abutment 67 and the cylinder head 30 is an expansive coil spring 59 arranged to bias 'the intake valve e2 toward closed position.

Mounted upon the cylinder head 50 is a plurality of brackets 70, one of which is shown in Figure 2, secured to the cylinder head construction. The brackets 70 support a shaft 72 extending longitudinally of the cylinder head. Rocker arms '74 are provided for actuating the valves 62. Each of the rocker arms is provided with a bushing or hearing member 75 for jcu'rnally supporting the rocker arm upon shaft '72. An operating rod 77 is provided for each rocker arm which engages an adjustable abutment 79 carriedby the rocker arm.

The lower end of each operating arm 7'? is disposed in the path of a suitable cam (not shown) formed on the camshaft '2 2,whereby the intake valve 62 of each cylinder is opened to admit fuel-and-air mixture into the cylinder at the proper period in the cycle of engine operation. During anopen-ing cycle of an intake valve 62, the rod 77 is moved upwardly, causing a counterclockwise movement of the rocker arm 7 as viewed in Figure 2,causing valve 62 tobe moved downward to establish communication between the port so and combustion chamber '63 formed in the cylinder head above each cylinder. v

Each'cylinder is provided with an exhaust valve normal-1y closing an exhaust port 82, which is connected with'an exhaust manifold, a portion of which is shown at '83, for conveying exhaust or burned gases from the engine. 'An expansive 'coil spring 85 is associated with 'e' ache'xha'ust valve 'and serves to bias the exhaust valve to closed position. Each exhaust valve is mounted in a suitable guide or'bushing 86 and is adapted to be actuated from cam means (not shown) formed on the camshaft 22.

A spark plug or mixture-igniting means 83 is disposed adjacent eachof'the combustion chambers 63, the spark plugs beingconne'cted with a suitable electric current distributing means'or igriiter to ignite in proper firing order the fuel-and-air'mixtures or charges in the com- The engine block 10 is formed with passageways 9t) surrounding the cylinders "for receiving liquid for cooling the en- The cylinder head 30 and manifold construction 32 are also formed with passages or chambers 92 to accommodate the circulation of cooling liquid to prevent overheating'of the cylinder head and manifold of the engine.

vention is illustrated in Figures 2 and 3. In the form shown, the manifold arrangement is cast or molded as an integral part of the cylinder head construction 32, al though it is to be understood that the manifold construction may be fabricated as an independent member adapted to be secured to a cylinder head construction. As shown in Figure 3, the manifold construction is formed with chambers 38 and 40 spaced lengthwise of the cylinder head and preferably aligned as shown.

The manifold chamber 38 is adapted to supply fueland-air mixture to one group of cylinders, namely, the first three cylinders of the engine, through transversely arranged passages 100, 101 and 102. The chamber 40 is adapted to convey fuel-and-air mixture to the other three cylinders of the engine through the transversely extending passageways 103, 104 and 1115. The manifold chamber or section 311 is adapted to receive fuel-and-air mixture from the carburetor 42, and the manifold chamher or section 411 is adapted to receive fuel-and-air mixture from the second carburetor 44. One of the carburetors is disposed above each of the risers or vertical passages 108 and 109 formed in the chambers 38 and 40, respectively.

Starting with #1 cylinder at the front of the engine block, the firing order or order of ignition of mixture in the engine cylinders is 1536-24, indicated in firing sequence by A, B, C, D, E and F in Figure 3. Hence, it will be seen that no two cylinders of a group receive in succession charges of fuel-and-air mixture from one carburetor. A charge of mixture is supplied by one carburetor to a "cylinder of one group, and the next cylinder in firing order receives its fuel-and-air mixture through the other manifold section from the other carburetor.

If no communication or passage were established be tween the manifold sections or chambers, each carburetor would be brought into operation only during the period in which alternate cylinders of the firing order require mixture from the carburetors; hence, each carburetor would have a period of inaction, that is, a period during which no air-and fuel mixture would be delivered by the carburetor. As time is required to initiate the flow of air set up by suction or reduced pressure by the downward movement of a piston in a cylinder through the carburetor, the engine cylinders would not receive proper and uniform charges of fuel-and-air mixture.

Inthe present invention, restricted communication is provided between manifold chambers or sections 38 and 40 as shown in Figure 3. The walls of the manifold construction intermediate the chambers 38 and 41 are shaped as shown at 112 to form a passage 114, establishing communication between manifold chambers 38 and 40. ,The passage preferably is configurated with a comparatively short zone 116 of a diameter providing the desired restricted flow of gas from one manifold chamber to the other, tending to equalize pressures in the manifold chambers. The restricted zone or portion 116 is joined to each of the manifold chambers 38 and 40 by tapered or frusto-conical wall portions 118. This passage configuration is generally of Venturi character wherein the restricted zone or portion 116 forms a so-called choke band cooperating with the tapered zones or portions to facilitate flow or transfer of fuel-and-air mixture between the manifold chambers.

The passage 114 provides a pressure equalization or balancing means between the manifold chambers. One of the major functions of the passage is to assure continuity of flow of fuel mixture through each of the carburetors at all times, during engine operation. A practical example of the mixture feed cycles is as follows. When the piston in #1 cylinder is moving downwardly during a fuel mixture intake stroke, the inlet valve 62 of this cylinder is in open position, and fuel-and-air mixture is delivered by carburetor 42 through manifold 38 and transverse passage 100 into combustion chamber 63 of #1 cylinder. After the piston in #1 cylinder reaches its lowermost position and begins its return or upward movement, valve 62 closes, a full charge of fuel-and-air mixture having been delivered into #1 cylinder. At the start of upward movement of the piston 56 in #1 cylinder on the compression stroke, the piston in #5 cylinder begins its downward movement of an intake stroke, the intake valve for #5 cylinder is opened, and fuel-and-air mixture is delivered from carburetor 44 through manifold 40 and transverse passage 1114 into #5 cylinder. Substantial reduced pressure or suction exists in the manifold chamber 40 and, through the provision of restricted passage 114, is effective to a reduced degree, dependent upon the size of passage 114, upon manifold chamber 38 and carburetor 42, to continue flow of fuel and air through carburetor 42 in reduced volume.

During the above-described period of engine operation and the intake cycle of #5 cylinder, the major amount of fuel and air for #5 cylinder is supplied by carburetor 44 and, due to the presence of restricted passage 114, only a very small or minor amount of fuel-and-air mixture is supplied by carburetor 42. When the piston in #5 cylinder reaches its lowermost position, the intake valve for #5 cylinder closes, and at the same time, the piston in #3 cylinder begins its downward or suction stroke of the intake cycle therefor. The flow of air and fuel through carburetor 42 is then increased, due to the substantial reduced pressure or suction set up in manifold chamber 38 by downward movement of the piston in #3 cylinder. The flow of fuel-and-air mixture from carburetor 4-2 into the manifold 38 is reduced under the influence of suction in #5 cylinder effective through passage 11 1; but such reduced flow is sufiicient so that when the suction in #3 cylinder becomes effective on manifold 38, the rate and volume of flow of air and fuel from carburetor 42 are simply increased to supply the proper charge to #3 cylinder.

This cycle continues for all of the cylinders during engine operation. Thus, in periods when the respective carburetors are not supplying major charges of fuel-andair mixture into the engine cylinders, continuity of flow of fuel and air, even though of reduced volume, is main tained through each carburetor. Some suction or reduced pressure is effective at all times upon the carburetors, establishing some mixture flow, so that it is never necessary for suction of an intake cycle of a cylinder to start the flow of air and fuel through a carburetor.

I Through this arrangement, the operation of the engine is very smooth; and through the use of a plurality of carburetors, the distance traversed by the mixture from any one carburetor to the cylinders being supplied with fuel and air therefrom is relatively short, so that the mixture of required volume is delivered into the cylinders with a minimum of friction and in shorter periods of time than in an engine where all of the cylinders receive their mixture charges from a single carburetor. It has been found that the arrangement utilizing a carburetor for a limited number of cylinders with a restricted passage between the manifold sections for each group of cylinders results in obtaining substantially increased horsepower from the engine without any increase in fuel consumption as the fuel efliciency is substantially improved.

The restricted passage provided by choke band 116 may be of different cross-sectional areas, depending upon the size of the engine with which the manifold arrangement is utilized as well as the number of cylinders connected with each manifold chamber. In actual test upon a 6-cylinder engine of the character shown in the drawings, having a piston displacement of 161 cubic inches, it has been found that the restricted zone or portions 116 of the passage 114 should be approximately inch in diam eter and approximately one inch in length. This proportion for a 6-cylinder engine of the above-mentioned displacement has been found to effect an increase of up to 10 H. P. as compared with a single carburetor and conventional, single-chamber manifold construction.

In the form of manifold construction shown in Figure 3, the restricted passage between manifold chambers 38 and 49 is formed by walls of the manifold construction cast integrally therewith. Figure 4 illustrates a modified form of arrangement shown in Figure 3 which embodies a removable member formed with the restricted passage, facilitating modification of the size of the restricted passage, if desired. As illustrated in Figure 4, the manifold construction 32 is formed with manifold sections or chambers 38 and 40 spaced lengthwise of the cylinder head in the same manner as that shown in Figure 3. The wall portion 125, disposed between chambers 38 and 40', is provided with a bore to snugly receive a member or tube 127. The member 127 is formed with a passageway 114 provided with a choke band portion 116 and tapered or frusto-conical wall portions 113' for establishing restricted communication between the manifold chambers. The ends of the manifold construction 32 are provided with access openings 130 which are closed by means of Scaling plugs 132. in assembly, member 127, formed with an exterior diameter to establish a press or snug fit with the bore in the wall portion 125 of the manifold construction, is forced into the position shown in Fig ure 4 by a suitable tool inserted in one of the openings 13%. After member 127 is disposed in the position shown in Figure 4, the end plates or plugs 132 are inserted to close the ends of the manifold chambers. The operation of the construction shown in Figure 4 is substantially the same as that of the form shown in Figure 3. If it is desired to change the size of the passageway, the closure plates 132 may be removed, member 127 driven out of the bore in wall 125, and the passage in member 127 modified, or a new member having a passage of a different size inserted between the manifold chambers 38 and 40, after which the closure members 132 are returned to the ends of the manifold chambers.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

7. claim:

1. In combination with an internal-combustion engine formed with a plurality of cylinders, a manifold construction arranged to distribute combustible mixture to the cylinders, said manifold construction being formed with a plurality of longitudinally aligned chambers, each of said chambers being adapted to receive combustible mixture from an independent charge-forming device, each of said chambers being arranged to convey combustible mixture to a group of cylinders of the engine, and a Venturishaped passage within the manifold construction for establishing restricted communication between adjacent chambers.

2. In combination with an internal-combustion engine having a plurality of cylinders, a manifold construction oil having a plurality of longitudinally spaced chambers formed therein, said chambers being arranged to convey combustible mixture to groups of cylinders of the engine, each of said chambers being arranged to receive combustible mixture from an independent charge-forming device, each of said chambers having a centrally arranged riser passage in communication with one of the chargeforming devices, transverse passages for establishing communication between each manifold chamber and the cylinders of the group supplied with fuel-and-air mixture therefrom, the wall portion of the manifold construction intermediate the manifold chambers being shaped to form a Venturi-shaped passage for establishing restricted com munication between adjacent manifold chambers.

3. In combination with an internal-combustion engine having a plurality of cylinders, a manifold construction for distributing combustible mixture to the engine cylinders, said manifold construction being formed with two manifold chambers arranged in spaced relation, each of said chambers being adapted to convey combustible mixture to one group of engine cylinders, each of said chambers having a riser passage centrally disposed with respect to the chamber, said riser passages respectively communicating with separate charge-forming devices, each of said chambers being in communication with transverse passages for conveying fuel-and-air mixture from each chamber to the group of cylinders connected therewith, and a tubular member disposed within the manifold construction between the manifold chambers, said tubular member having a Venturi-shaped passage of restricted area establishing communication between the chambers tending to equalize the pressures in said manifold chambers.

4. in combination with an internal-combustion engine having a block formed with six cylinders and having a separable cylinder head, a pair of spaced, elongated manifold chambers integrally formed in the cylinder head, each of said chambers being arranged to supply fuel-andair mixture to a group of three cylinders, said cylinder head being formed with two groups of transversely arranged passages establishing communication between each of the chambers and the cylinders adapted to be supplied with fuel-and-air mixture therefrom, each of said cham bers having a riser passage centrally disposed with respect to the chamber, a carburetor for each chamber supported upon the cylinder head and disposed above the riser passage of the adjacent manifold chamber, and a Venturishaped duct axially aligned with the chambers for establishing restricted communication between the chambers.

References Cited in the file of this patent UNITED STATES PATENTS 1,929,637 Hall .Oct. 10, 19.33 2,315,215 Maybach Mar. 30, 1943 2,323,442 Beard July 6, 1943 2,337,050 Jackson Dec. 21, 1943 

